The Motion Picture Experts Group (MPEG) of the International Organization for Standardization and the International Electrotechnical Commission has developed the MPEG-2 standard capable of coding standard-definition television at bit rates of approximately 3-15 Mbps and high-definition television at approximately 15-30 Mbps. Further, as an enhancement over its MPEG-1 predecessor, MPEG-2 adds multiple channel surround sound audio coding.
The MPEG-2 coding, versus its approximate television equivalent, operates at a reduced bit rate by removing redundant information from the video/audio signal at the coder prior to transmitting the video/audio signal. The redundant information may then be added back at the decoder. The MPEG-2 bit rate reduction scheme relies both on special and temporal redundancy and psychovisual redundancy to reduce the bit rate of a video/audio signal substantially without detection by the viewer. Temporal redundancy may refer to pixel values that are not independent but are correlated to their neighbors both within the same video frame and across multiple video frames. Psychovisual redundancy may refer to limits for a viewer's eyes for fine detail at their vision periphery and around video shot changes.